sudo pacman -Sy yay # easy tool to help install AUR packages
yay makemkv
# select aur/makemkv and aur/makemkv-libaacs and install them
sudo usermod -G optical -a $USER # grants current user access to the optical drive
sudo modprobe sg # load the 'sg' (SCSI Generic) module
echo 'sg' | sudo tee /etc/modules-load.d/sg.conf # ensures sg will load on future boots
Now log out and back in so your new group membership will take effect
use makemkv
or search for 'MakeMKV' in your DE's menus. Don't forget to register!